When stains occur on plastic in the course of machine dishwashing, this is usually caused by very intensely colored foods such as curry, paprika, tomatoes, red cabbage, ketchup, carrots, etc., which in the form of food residues are introduced into the dishwasher. Stains on plastic, such as plastic dishware, result in consumer dissatisfaction, since, although the affected plastic dishware remains undamaged on a purely functional level, this is perceived by many consumers as detrimental to the appearance, insufficiently cleaned, or at least esthetically displeasing.
Compounds for reducing the staining of plastics are described in Patent Application WO 02/064720, for example. The cited publication discloses that copolymers based on hydrophobically modified polycarboxylates suppress the staining of plastics.
International Patent Application WO 03/095602 discloses a method for removing colored soils on plastic, using a component having a density of 0.6 to 1 g/L, in particular paraffin oil and similar hydrocarbons, olive oil, and soybean oil.
WO 2010/078979 discloses the use of porous polyamide particles and synthetic layered silicates for reducing the staining of plastic dishware.
According to German Patent Application DE 10104470, copolymers which contain at least two monoethylenically unsaturated monomers, one of which preferably represents an α-olefin having 10 or more carbon atoms, are used in machine dishwashing detergents for inhibiting the staining of plastic objects.
The object of the present invention is to provide further compounds which at least reduce the occurrence of stains on plastics, due to colored food residues, in the course of machine dishwashing.
It has surprisingly been found that this object is achieved by certain amphiphilic block copolymers which contain dienes as hydrophobic monomers.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.